Lighting and Illumination

Appropriate quality and placement of lighting can enhance an environment and increase comfort and safety. Pedestrians may assume that their ability to see oncoming headlights means motorists can see them at night; however, without sufficient lighting, motorists may not be able to see pedestrians in time to stop.

A single luminaire placed directly over the crosswalk does not adequately illuminate the pedestrian for the approaching motorist. It is best to place streetlights along both sides of arterial streets and provide a consistent level of lighting along a roadway. This includes lighting pedestrian crosswalks and approaches to the crosswalks. A study conducted by the Virginia Tech Transportation Institute found that 20 lx (a unit of illuminance) was necessary for motorists to detect a pedestrian in the crosswalk. To achieve 20 lx, the luminaire should be placed 10 feet from the crosswalk, in between the approaching vehicles and the crosswalk. At intersections, the luminaires should also be placed before the crosswalk on the approach into the intersection. This differs from traditional placement of luminaires over the actual intersection.13

In commercial areas or in downtown areas, specialty pedestrian-level lighting may be placed over the sidewalks to improve pedestrian comfort, security, and safety. Well-lit pedestrian areas make people walking through the area feel safer. Streetlights and building lights can enhance the ambiance of the area and the visibility of pedestrians in commercial areas with nighttime pedestrian activity. Nighttime pedestrian crossing areas may be supplemented with brighter or additional lighting.

Purpose

Roadway lighting has often focused on the needs of the motorist and not necessarily the safety of the pedestrian. However, it is important to consider lighting that illuminates pedestrian crosswalks and reduces glare to motorists. Pedestrian fatalities occur disproportionately during dark conditions. Adequate roadway lighting enhances the safety of all roadway users, while pedestrian-scale lighting improves nighttime security and enhances commercial districts.

Considerations

• Install lighting on both sides of wide streets and streets in commercial districts.
• Use uniform lighting levels.
• Place lights in advance of midblock and intersection crosswalks on both approaches to illuminate the front of the pedestrian and avoid creating a silhouette.

Estimated Cost

Infrastructure

Description

Median

Average

Min. Low

Max. High

Cost Unit

# of Sources (Observations)

Lighting

In-pavement Lighting

$18,250

$17,620

$6,480

$40,000

Total

4(4)

Lighting

Streetlight

$3,602

$4,882

$310

$13,895

Each

12(17)

Lighting varies based on the fixture type, manufacturer differences, roadway widths, project-specific factors, and utility service agreement. Usually, in-pavement lights are installed as a system, which is the reason the total cost is included here, as opposed to an individual light cost. Also, though not included above, average approximate underpass lighting costs can range from $350 to $3,400 each, and crosswalk lighting can range from approximately $10,750 to $42,000 per crosswalk.

Safety Effects

A summary of studies that have looked at the safety effects of lighting and illumination can be found here.